| Message ID | 1515521301-4375-1-git-send-email-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
On úterý 9. ledna 2018 19:08:21 CET, Geert Uytterhoeven wrote: > Since commit f11a04464ae57e8d ("i2c: gpio: Enable working over slow > can_sleep GPIOs"), probing the i2c RTC connected to an i2c-gpio bus on > r8a7740/armadillo fails with: > > rtc-s35390a 0-0030: error resetting chip > rtc-s35390a: probe of 0-0030 failed with error -5 > > More debug code reveals: > > i2c i2c-0: master_xfer[0] R, addr=0x30, len=1 > i2c i2c-0: NAK from device addr 0x30 msg #0 > s35390a_get_reg: ret = -6 > > Commit 02e479808b5d62f8 ("gpio: Alter semantics of *raw* operations to > actually be raw") moved open drain/source handling from > gpiod_set_raw_value_commit() to gpiod_set_value(), but forgot to take > into account that gpiod_set_value_cansleep() also needs this handling. > The i2c protocol mandates that i2c signals are open drain, hence i2c > communication fails. > > Fix this by adding the missing handling to gpiod_set_value_cansleep(), > using a new common helper __gpiod_set_value_nocheck(). > > Fixes: 02e479808b5d62f8 ("gpio: Alter semantics of *raw* > operations to actually be raw") > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > The bad gpio commit is in v4.15-rc1 and later. > The i2c commit exposing this is not yet upstream, but in i2c/for-next. > --- > drivers/gpio/gpiolib.c | 26 ++++++++++++++------------ > 1 file changed, 14 insertions(+), 12 deletions(-) > > diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c > index 358bce6e798b476c..7761d632a5b0dd20 100644 > --- a/drivers/gpio/gpiolib.c > +++ b/drivers/gpio/gpiolib.c > @@ -2927,6 +2927,18 @@ void gpiod_set_raw_value(struct > gpio_desc *desc, int value) > } > EXPORT_SYMBOL_GPL(gpiod_set_raw_value); > > +static void __gpiod_set_value_nocheck(struct gpio_desc *desc, int value) > +{ > + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) > + value = !value; > + if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) > + gpio_set_open_drain_value_commit(desc, value); > + else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) > + gpio_set_open_source_value_commit(desc, value); > + else > + gpiod_set_raw_value_commit(desc, value); > +} > + > /** > * gpiod_set_value() - assign a gpio's value > * @desc: gpio whose value will be assigned > @@ -2941,16 +2953,8 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value); > void gpiod_set_value(struct gpio_desc *desc, int value) > { > VALIDATE_DESC_VOID(desc); > - /* Should be using gpiod_set_value_cansleep() */ > WARN_ON(desc->gdev->chip->can_sleep); > - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) > - value = !value; > - if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) > - gpio_set_open_drain_value_commit(desc, value); > - else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) > - gpio_set_open_source_value_commit(desc, value); > - else > - gpiod_set_raw_value_commit(desc, value); > + __gpiod_set_value_nocheck(desc, value); > } > EXPORT_SYMBOL_GPL(gpiod_set_value); > > @@ -3277,9 +3281,7 @@ void gpiod_set_value_cansleep(struct > gpio_desc *desc, int value) > { > might_sleep_if(extra_checks); > VALIDATE_DESC_VOID(desc); > - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) > - value = !value; > - gpiod_set_raw_value_commit(desc, value); > + __gpiod_set_value_nocheck(desc, value); > } > EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep); > I realize that I'm late to the party (a merge request has been sent), but I can confirm that I tested that this still works for a bitbang I2C over GPIO pins connected to MAX14830 managed by max310x. Tested-By: Jan Kundrát <jan.kundrat@cesnet.cz> Cheers, Jan
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 358bce6e798b476c..7761d632a5b0dd20 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2927,6 +2927,18 @@ void gpiod_set_raw_value(struct gpio_desc *desc, int value) } EXPORT_SYMBOL_GPL(gpiod_set_raw_value); +static void __gpiod_set_value_nocheck(struct gpio_desc *desc, int value) +{ + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + value = !value; + if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) + gpio_set_open_drain_value_commit(desc, value); + else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) + gpio_set_open_source_value_commit(desc, value); + else + gpiod_set_raw_value_commit(desc, value); +} + /** * gpiod_set_value() - assign a gpio's value * @desc: gpio whose value will be assigned @@ -2941,16 +2953,8 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value); void gpiod_set_value(struct gpio_desc *desc, int value) { VALIDATE_DESC_VOID(desc); - /* Should be using gpiod_set_value_cansleep() */ WARN_ON(desc->gdev->chip->can_sleep); - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) - value = !value; - if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) - gpio_set_open_drain_value_commit(desc, value); - else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) - gpio_set_open_source_value_commit(desc, value); - else - gpiod_set_raw_value_commit(desc, value); + __gpiod_set_value_nocheck(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_value); @@ -3277,9 +3281,7 @@ void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) { might_sleep_if(extra_checks); VALIDATE_DESC_VOID(desc); - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) - value = !value; - gpiod_set_raw_value_commit(desc, value); + __gpiod_set_value_nocheck(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep);
Since commit f11a04464ae57e8d ("i2c: gpio: Enable working over slow can_sleep GPIOs"), probing the i2c RTC connected to an i2c-gpio bus on r8a7740/armadillo fails with: rtc-s35390a 0-0030: error resetting chip rtc-s35390a: probe of 0-0030 failed with error -5 More debug code reveals: i2c i2c-0: master_xfer[0] R, addr=0x30, len=1 i2c i2c-0: NAK from device addr 0x30 msg #0 s35390a_get_reg: ret = -6 Commit 02e479808b5d62f8 ("gpio: Alter semantics of *raw* operations to actually be raw") moved open drain/source handling from gpiod_set_raw_value_commit() to gpiod_set_value(), but forgot to take into account that gpiod_set_value_cansleep() also needs this handling. The i2c protocol mandates that i2c signals are open drain, hence i2c communication fails. Fix this by adding the missing handling to gpiod_set_value_cansleep(), using a new common helper __gpiod_set_value_nocheck(). Fixes: 02e479808b5d62f8 ("gpio: Alter semantics of *raw* operations to actually be raw") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- The bad gpio commit is in v4.15-rc1 and later. The i2c commit exposing this is not yet upstream, but in i2c/for-next. --- drivers/gpio/gpiolib.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-)